/*
silverPDF is sponsored by Aleyant Systems (http://www.aleyant.com)

silverPDF is based on PdfSharp (http://www.pdfsharp.net) and iTextSharp (http://itextsharp.sourceforge.net)

Developers: Ai_boy (aka Oleksii Okhrymenko)

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above information and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR SPONSORS
BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

*/
#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2008 empira Software GmbH, Cologne (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Diagnostics;
using System.Collections;
using System.Reflection;
using System.Text;
using System.IO;
using PdfSharp.Internal;
using PdfSharp.Pdf;
using PdfSharp.Pdf.IO;

namespace PdfSharp.Pdf.Advanced
{
  /// <summary>
  /// Provides access to the internal document data structures. This class prevents the public
  /// interfaces from pollution with internal functions.
  /// </summary>
  public class PdfInternals  // TODO: PdfDocumentInternals... PdfPageInterals etc.
  {
    internal PdfInternals(PdfDocument document)
    {
      this.document = document;
    }
    PdfDocument document;

    /// <summary>
    /// Gets or sets the first document identifier.
    /// </summary>
    public string FirstDocumentID
    {
      get { return this.document.trailer.GetDocumentID(0); }
      set { this.document.trailer.SetDocumentID(0, value); }
    }

    /// <summary>
    /// Gets the first document identifier as GUID.
    /// </summary>
    public Guid FirstDocumentGuid
    {
      get { return GuidFromString(this.document.trailer.GetDocumentID(0)); }
    }

    /// <summary>
    /// Gets or sets the second document identifier.
    /// </summary>
    public string SecondDocumentID
    {
      get { return this.document.trailer.GetDocumentID(1); }
      set { this.document.trailer.SetDocumentID(1, value); }
    }

    /// <summary>
    /// Gets the first document identifier as GUID.
    /// </summary>
    public Guid SecondDocumentGuid
    {
      get { return GuidFromString(this.document.trailer.GetDocumentID(0)); }
    }

    Guid GuidFromString(string id)
    {
      if (id == null || id.Length != 16)
        return Guid.Empty;

      StringBuilder guid = new StringBuilder();
      for (int idx = 0; idx < 16; idx++)
        guid.AppendFormat("{0:X2}", (byte)id[idx]);

      return new Guid(guid.ToString());
    }

    /// <summary>
    /// Gets the catalog dictionary.
    /// </summary>
    public PdfCatalog Catalog
    {
      get { return this.document.Catalog; }
    }

    /// <summary>
    /// Returns the object with the specified Identifier, or null, if no such object exists.
    /// </summary>
    public PdfObject GetObject(PdfObjectID objectID)
    {
      return document.irefTable[objectID].Value;
    }

    /// <summary>
    /// Returns the PdfReference of the specified object, or null, if the object is not in the
    /// document's object table.
    /// </summary>
    public static PdfReference GetReference(PdfObject obj)
    {
      if (obj == null)
        throw new ArgumentNullException("obj");
      return obj.Reference;
    }

    /// <summary>
    /// Gets the object identifier of the specified object.
    /// </summary>
    public static PdfObjectID GetObjectID(PdfObject obj)
    {
      if (obj == null)
        throw new ArgumentNullException("obj");
      return obj.ObjectID;
    }

    /// <summary>
    /// Gets the object number of the specified object.
    /// </summary>
    public static int GetObjectNumber(PdfObject obj)
    {
      if (obj == null)
        throw new ArgumentNullException("obj");
      return obj.ObjectNumber;
    }

    /// <summary>
    /// Gets the generation number of the specified object.
    /// </summary>
    public static int GenerationNumber(PdfObject obj)
    {
      if (obj == null)
        throw new ArgumentNullException("obj");
      return obj.GenerationNumber;
    }

    /// <summary>
    /// Gets all indirect objects ordered by their object identifier.
    /// </summary>
    public PdfObject[] AllObjects
    {
      get
      {
        PdfReference[] irefs = this.document.irefTable.AllReferences;
        int count = irefs.Length;
        PdfObject[] objects = new PdfObject[count];
        for (int idx = 0; idx < count; idx++)
          objects[idx] = irefs[idx].Value;
        return objects;
      }
    }

    /// <summary>
    /// Creates the indirect object of the specified type, adds it to the document, and
    /// returns the object.
    /// </summary>
    public T CreateIndirectObject<T>() where T : PdfObject
    {
      T result = null;
      ConstructorInfo ctorInfo = typeof(T).GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.ExactBinding,
        null, new Type[] { typeof(PdfDocument) }, null);
      if (ctorInfo != null)
      {
        result = (T)ctorInfo.Invoke(new object[] { this.document });
        Debug.Assert(result != null);
        AddObject(result);
      }
      Debug.Assert(result != null, "CreateIndirectObject failed with type " + typeof(T).FullName);
      return result;
    }

    /// <summary>
    /// Adds an object to the PDF document. This operation and only this operation makes the object 
    /// an indirect object owned by this document.
    /// </summary>
    public void AddObject(PdfObject obj)
    {
      if (obj == null)
        throw new ArgumentNullException("obj");
      if (obj.Owner == null)
        obj.Document = this.document;
      else if (obj.Owner != this.document)
        throw new InvalidOperationException("Object does not belong to this document.");
      this.document.irefTable.Add(obj);
    }

    /// <summary>
    /// Removes an object from the PDF document.
    /// </summary>
    public void RemoveObject(PdfObject obj)
    {
      if (obj == null)
        throw new ArgumentNullException("obj");
      if (obj.Reference == null)
        throw new InvalidOperationException("Only indirect objects can be removed.");
      if (obj.Owner != this.document)
        throw new InvalidOperationException("Object does not belong to this document.");

      this.document.irefTable.Remove(obj.Reference);
    }

    /// <summary>
    /// Returns an array containing the specified object as first element follows by its transitive
    /// closure. The closure of an object are all objects that can be reached by indirect references. 
    /// The transitive closure is the result of applying the calculation of the closure to a closure
    /// as long as no new objects came along. This is e.g. useful for getting all objects belonging 
    /// to the resources of a page.
    /// </summary>
    public PdfObject[] GetClosure(PdfObject obj) // TODO: "..., bool transitive)"
    {
      PdfReference[] references = this.document.irefTable.TransitiveClosure(obj);
      int count = references.Length + 1;
      PdfObject[] objects = new PdfObject[count];
      objects[0] = obj;
      for (int idx = 1; idx < count; idx++)
        objects[idx] = references[idx - 1].Value;
      return objects;
    }

    /// <summary>
    /// Writes a PdfItem into the specified stream.
    /// </summary>
    // This function exists to keep PdfWriter and PdfItem.WriteObject internal.
    public void WriteObject(Stream stream, PdfItem item)
    {
      // Never write an encrypted object
      PdfWriter writer = new PdfWriter(stream, null);
      writer.Options = PdfWriterOptions.OmitStream;
      item.WriteObject(writer);
    }

    /// <summary>
    /// The name of the custuom value key.
    /// </summary>
    public string CustomValueKey = "/PdfSharp.CustomValue";
  }
}
